1. Field of the Invention
The present invention relates to a multilayer color photographic light-sensitive material which provides color images having good color purity, sharpness and graininess.
2. Description of the Prior Art
It is well known that couplers, that is to say, compounds capable of forming dyes such as indophenols, indoanilines, indamines, azomethines, phenoxazines, phenazines, and the like, on coupling with oxidized primary aromatic amine developing agents are used in color photographic materials containing silver halide emulsion layers.
On the other hand, a silver halide color photographic material based on the substractive three primary color principle has, as a layer structure, a silver halide emulsion layer to form a yellow color due to the action of blue light, a silver halide emulsion layer to form a color due to the action of green light, and a silver halide emulsion layer to form a cyan color due to the action of red light. When a color-forming system wherein a primary aromatic amine developing agent and couplers are used is employed in the color image formation of such a color photographic material, an acylacetamide derivative or a dibenzoylmethane derivative is usually used as the yellow-forming coupler, a 5-pyrazolone derivative, a cyanoacetyl derivative, an indazolone derivative, or a pyrazolonebenzimidazole derivative is usually used as the magenta-forming coupler, and a phenol derivative or an .alpha.-naphthol derivative is usually used as the cyan-forming coupler.
In the multilayer color photographic materials as described above, various characteristics are required in the color images formed.
One characteristic is that when color images are formed in one emulsion layer unit, color images are not formed in other emulsion layer units in order to prevent color mixing. That is to say, images with good color purity is desired.
Another characteristic is that fine details of the color images are clear, that is, the images have good sharpness.
Still another characteristic is that the color images appear to be grainless, that is, the images have good graininess.
A still further characteristic is that images can be reproduced with fidelity over a wide range of exposure amount, that is, a wide exposure latitude.
Various attempts have been made to provide multilayer color photographic light-sensitive materials having these characteristics. However, these attempts have not yet proven to be satisfactory.
For instance, in using a coupler which releases a compound having a mercapto group on coupling with an oxidized primary aromatic amine developing agent as described in U.S. Pat. No. 3,227,554, while the sharpness, graininess and exposure latitude are improved to some extent, no improvement in the color purity is effectively achieved. This defect is particularly marked when a fine grain silver halide emulsion is used.
Also using a development inhibitor releasing hydroquinone derivative represented by the general formula (II) described hereinafter, such as is described, for example, in U.S. Pat. No. 3,379,529, the same is obtained as when the above-described coupler which releases a compound having a mercapto group on coupling with an oxidized primary aromatic amine developing agent is used.
Further when a two-equivalent coupler is used, the thickness of the emulsion layer can be reduced resulting in an improvement in the sharpness. However, the color purity and graininess rather tend to decrease.
Furthermore, in using an interlayer color correction coupler (hereinafter designated as an "ICC coupler") such as is described, for example, in U.S. Pat. application Ser. Nos. 454,525, filed Mar. 25, 1974 and 467,539, filed May 6, 1974, while the color purity is improved due to color correction effects due to the so-called interlayer effects and the sharpness is improved due to edge effects, the graininess is not sufficiently improved.
The term "ICC coupler" as used herein means a coupler as defined in U.S. Pat. application Ser. No. 467,539, filed May 6, 1974 and means a coupler which exhibits interlayer effects together with less development inhibiting effects in the developing layer when such a coupler is used in a multilayer photographic light-sensitive material and as the result has a "color correction function." The term "interlayer effects" means development inhibiting effects in one or more of the other layers depending on the development of one layer of a multilayer material. One method to achieve these effects is to use development inhibitors which are released imagewise depending on the development in one emulsion layer and are diffused to one or more other layers. The "development inhibiting effects" in the developing layer are those which reduce the gradation of an emulsion layer in which the compound is incorporated.